處理Android 中的互聯網連接變化

問題集中在需要一個可以監視互聯網連接變化的廣播接收器，因為現有代碼僅檢測連接變化。

為了解決這個問題，這裡有一個替代方法：

public class NetworkUtil {
    public static final int TYPE_WIFI = 1;
    public static final int TYPE_MOBILE = 2;
    public static final int TYPE_NOT_CONNECTED = 0;

    public static int getConnectivityStatus(Context context) {
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        if (activeNetwork != null) {
            if (activeNetwork.getType() == ConnectivityManager.TYPE_WIFI)
                return TYPE_WIFI;

            if (activeNetwork.getType() == ConnectivityManager.TYPE_MOBILE)
                return TYPE_MOBILE;
        }
        return TYPE_NOT_CONNECTED;
    }
}

此方法決定設備是否連接到 WiFi 或行動數據。

public class NetworkChangeReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(final Context context, final Intent intent) {
        int status = NetworkUtil.getConnectivityStatus(context);
        if ("android.net.conn.CONNECTIVITY_CHANGE".equals(intent.getAction()) {
            if (status == NetworkUtil.TYPE_NOT_CONNECTED) {
                // Handle loss of internet connectivity
            } else {
                // Handle restoration of internet connectivity
            }
        }
    }
}

此 BroadcastReceiver 監視連線狀態變更並根據目前狀態觸發操作。請記得在 AndroidManifest.xml 中包含適當的權限並註冊接收器：